Accessing hardware peripherals (SDVX)
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Contents
History[edit | edit source]
| Version | Date | SDVX version | Hardware Part Nr | Notes |
|---|---|---|---|---|
| 1.0.0 | October 2018 | SDVX 1.0.1 | SDV03 or SDV04 |
Introduction[edit | edit source]
This is a quickstart guide to access the hardware peripheral from sysfs or kernel device nodes.
For more information regarding sysfs, go to its official page
For more information regarding kernel device driver, go to its official page
Peripherals[edit | edit source]
SD / MMC[edit | edit source]
SD device node is created by the linux kernel and mapped to multiple:
/dev/mmcblk{device}p{part}
where device is the SD device on the device tree and part is the part number
E.g. for an eMMC device with two partition:
root@sdv03-lite:~# ls -la /dev/mmcblk2* brw-rw---- 1 root disk 179, 0 Oct 4 11:06 /dev/mmcblk2 brw-rw---- 1 root disk 179, 8 Oct 4 11:06 /dev/mmcblk2boot0 brw-rw---- 1 root disk 179, 16 Oct 4 11:06 /dev/mmcblk2boot1 brw-rw---- 1 root disk 179, 1 Oct 4 11:06 /dev/mmcblk2p1 brw-rw---- 1 root disk 179, 2 Oct 4 11:06 /dev/mmcblk2p2 brw-rw---- 1 root disk 179, 24 Oct 4 11:06 /dev/mmcblk2rpmb root@sdv03-lite:~#
The partition can be seen using:
root@sdv03-lite:~# fdisk -l /dev/mmcblk2 Disk /dev/mmcblk2: 3.7 GiB, 3959422976 bytes, 7733248 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xcce0c36f Device Boot Start End Sectors Size Id Type /dev/mmcblk2p1 16384 278527 262144 128M c W95 FAT32 (LBA) /dev/mmcblk2p2 278528 4472831 4194304 2G 83 Linux root@sdv03-lite:~#
1-wire[edit | edit source]
The 1-wire device on SDVx carrier board contains the hardware-programmable information stored in factory or on the field.
Main information are:
- SOM configid: contains the factory programmed ID for HW SOM configuration - more information at the ConfigID page
- SOM uniqueid: contains the SOM unique identification - more information at the UniqueID page
- CB configid: contains the factory programmed ID for HW Carrier board configuration - more information at the ConfigID page
- CB uniqueid: contains the Carrier board unique identification - more information at the UniqueID page
ConfigID and UniqueID information can be gathered from sysfs using the following commands:
root@sdv03-lite:~# cat /proc/device-tree/som/configid 00000001root@sdv03-lite:~# root@sdv03-lite:~# cat /proc/device-tree/som/uniqueid e317d7c9:1a0151d4root@sdv03-lite:~# root@sdv03-lite:~# cat /proc/device-tree/cb/configid 0000002aroot@sdv03-lite:~# root@sdv03-lite:~# cat /proc/device-tree/cb/uniqueid b100001a:baed182droot@sdv03-lite:~#
LCD /backlight[edit | edit source]
The LCD framebuffer is mapped to /dev/fb0 device. Its configuration can be displayed using the fbset command:
root@sdv03-lite:~# fbset -fb /dev/fb0
mode "800x480-59"
# D: 33.000 MHz, H: 31.191 kHz, V: 59.298 Hz
geometry 800 480 800 480 16
timings 30303 128 128 15 30 2 1
rgba 5/11,6/5,5/0,0/0
endmode
root@sdv03-lite:~#
framebuffer[edit | edit source]
It is possible to test the framebuffer visualization using the fbi utility:
root@sdv03-lite:~# fbi -d /dev/fb0 -T 1 -a startSplash.ppm root@sdv03-lite:~#
where:
- -d /dev/fb0 means using the fb0 framebuffer device
- -T 1 means using the tty1 console
- -a means autoscale
fbi utility is a linux console framebuffer viewer that supports multiple images format: see more info on its man page
splash images[edit | edit source]
Many utilities or techniques can be used to display images during the boot process: one of them is to use fbsplash. See more info on its man page
fbsplash is part of busybox, so for a direct invocation, a symbolic link to busybox can be created:
root@sdv03-lite:~# ln -s /bin/busybox.nosuid /bin/fbsplash
backlight[edit | edit source]
The LCD backlight is PWM controlled and can be changed directly using the sysfs entry:
root@sdv03-lite:~# cat /sys/class/backlight/backlight/brightness 75 root@sdv03-lite:~# cat /sys/class/backlight/backlight/max_brightness 100 root@sdv03-lite:~# echo 100 > /sys/class/backlight/backlight/brightness root@sdv03-lite:~# echo 0 > /sys/class/backlight/backlight/brightness root@sdv03-lite:~#
Touchscreen[edit | edit source]
Touchscreen device is typically mapped by the kernel on the event0 device:
root@sdv03-lite:~# ls -la /dev/input total 0 drwxr-xr-x 3 root root 140 Oct 4 11:06 . drwxr-xr-x 12 root root 3280 Oct 4 11:06 .. drwxr-xr-x 2 root root 60 Oct 4 11:06 by-path crw-rw---- 1 root input 13, 64 Oct 4 11:06 event0 crw-rw---- 1 root input 13, 63 Oct 4 11:06 mice crw-rw---- 1 root input 13, 32 Oct 4 11:06 mouse0 lrwxrwxrwx 1 root root 6 Oct 4 11:06 touchscreen0 -> event0 root@sdv03-lite:~#
ts_lib[edit | edit source]
For testing the touchscreen behaviour, the ts_lib utilities can be used:
- touchscreen calibration
root@sdv03-lite:~# ts_calibrate xres = 800, yres = 480 Took 9 samples... Top left : X = 63 Y = 74 Took 3 samples... Top right : X = 726 Y = 81 Took 1 samples... Bot right : X = 722 Y = 441 Took 5 samples... Bot left : X = 73 Y = 437 Took 10 samples... Center : X = 411 Y = 248 -23.533630 1.066568 -0.007912 -25.745605 -0.008527 1.050538 Calibration constants: -1542300 69898 -518 -1687264 -558 68848 65536 root@sdv03-lite:~#
- touchscreen reported coordinates:
root@sdv03-lite:~# ts_test 1538653269.165704: 398 238 156 1538653269.165704: 398 238 156 1538653269.175700: 398 238 121 1538653269.185728: 398 238 112 1538653269.195718: 399 240 88 1538653269.205688: 399 241 70 1538653269.215709: 403 241 68 1538653269.225689: 405 240 79 1538653269.235738: 408 239 98 1538653269.245698: 410 239 102 1538653269.255713: 412 238 115 1538653269.265687: 414 237 130 1538653269.275710: 416 235 136 1538653269.285682: 418 234 161 1538653269.295709: 418 233 184 1538653269.305679: 418 232 189 1538653269.325669: 419 231 180 1538653269.335691: 419 233 125 1538653269.352710: 419 237 0 ^Csignal 2 caught root@sdv03-lite:~#
tslib and X11[edit | edit source]
For using tslib under X11 framework, it is required to configure X-Windows to use the touchscreen driver.
This is possible by adding an InputDevice section to /etc/X11/xorg.conf:
root@sdv03:~# cat /etc/X11/xorg.conf
Section "Device"
Identifier "i.MX Accelerated Framebuffer Device"
Driver "vivante"
Option "fbdev" "/dev/fb0"
Option "vivante_fbdev" "/dev/fb0"
Option "HWcursor" "false"
EndSection
Section "ServerFlags"
Option "BlankTime" "0"
Option "StandbyTime" "0"
Option "SuspendTime" "0"
Option "OffTime" "0"
EndSection
Section "InputDevice"
Identifier "tslib"
Driver "tslib"
Option "Device" "/dev/input/event0"
Option "ScreenNumber" "0"
Option "Width" "800"
Option "Height" "480"
Option "Rotate" "NONE"
Option "TslibDevice" "/dev/input/event0"
Option "CorePointer"
EndSection
root@sdv03:~#
X11[edit | edit source]
For touchscreen calibration under the X11 framework, the touchscreen should be calibrated using the xinput_calibrator utility:
root@sdv03-lite:~# xinit /etc/X11/Xsession --Xorg &
X.Org X Server 1.18.0
Release Date: 2015-11-09
X Protocol Version 11, Revision 0
Build Operating System: Linux 3.13.0-126-generic x86_64
Current Operating System: Linux test-noserialnumber 4.1.15-sdvx-1.0.1 #1 SMP PREEMPT Wed Oct 3 22:52:45 CEST 2018 armv7l
Kernel command line: root=/dev/mmcblk2p2 rootwait rw console=ttymxc2,115200 vmalloc=400M mtdparts=gpmi-nand:8M(nand-uboot),1M(nand-env1),1M(nand-env2),1M(nand-fdt),1M(nand-spare),8M(nand-kernel),6M(nand-splash),-(nand-ubi);spi0.0:1M(spi-uboot),256k(spi-env1),256k(spi-env2),512k(spi-dtb),8M(spi-kernel),4M(spi-splash),-(spi-free)
Build Date: 07 November 2017 10:46:08AM
Current version of pixman: 0.32.8
Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Oct 15 10:43:31 2018
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
root@sdv03-lite:~# export DISPLAY=:0
root@sdv03-lite:~# xinput_calibrator
Setting calibration data: 0, 799, 0, 479
Calibrating EVDEV driver for "TSC2007 Touchscreen" id=6
current calibration values (from XInput): min_x=0, max_x=799 and min_y=0, max_y=479
Doing dynamic recalibration:
Setting calibration data: 31, 763, 19, 474
--> Making the calibration permanent <--
copy the snippet below into '/etc/X11/xorg.conf.d/99-calibration.conf'
Section "InputClass"
Identifier "calibration"
MatchProduct "TSC2007 Touchscreen"
Option "Calibration" "31 763 19 474"
Option "SwapAxes" "0"
EndSection
root@sdv03-lite:~#
then copy the calibration data into the configuration file:
root@sdv03-lite:~# cat /etc/X11/xorg.conf
Section "Device"
Identifier "i.MX Accelerated Framebuffer Device"
Driver "vivante"
Option "fbdev" "/dev/fb0"
Option "vivante_fbdev" "/dev/fb0"
Option "HWcursor" "false"
EndSection
Section "ServerFlags"
Option "BlankTime" "0"
Option "StandbyTime" "0"
Option "SuspendTime" "0"
Option "OffTime" "0"
EndSection
Section "InputClass"
Identifier "calibration"
MatchProduct "TSC2007 Touchscreen"
Option "Calibration" "31 763 19 474"
Option "SwapAxes" "0"
EndSection
Audio[edit | edit source]
Audio device is controlled by the ALSA layer.
Two audio utilities can be used for easy access to the audio device:
alsamixeraplay
Many controls can be directly acrivated on command line using the amixer utility: here below a simple script for configuring the audio device
root@sdv03-lite:~# cat audio.sh amixer sset 'Speaker' on amixer sset 'Speaker Driver' on amixer sset 'Speaker Driver' 3 amixer sset 'Speaker Analog' 100 amixer sset 'Output Right From Right DAC' on amixer sset 'HP Right' on amixer sset 'HP Left' on amixer sset 'HP Driver' 9 amixer sset 'HP Driver' on amixer sset 'HP Analog' 95 amixer sset 'DAC' 150 amixer sset 'DAC Left Input' 'Mono' amixer sset 'DAC Right Input' 'Mono' amixer sset 'Output Left From Left DAC' on amixer sset 'Output Left From MIC1LP' on amixer sset 'Output Left From MIC1RP' on amixer sset 'Output Right From MIC1RP' on amixer sset 'Output Right From MIC1RP' on amixer sset 'MIC1RP P-Terminal' 'FFR 10 Ohm' amixer sset 'Output Right From Right DAC' on root@sdv03-lite:~#
For playing an audio file, it is enough to use aplay utility:
root@sdv03-lite:~# aplay test_stereo_44100Hz_16bit_PCM.wav Playing WAVE 'test_stereo_44100Hz_16bit_PCM.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo root@sdv03-lite:~#
Bluetooth[edit | edit source]
BT device can be accessed using standard tty device driver.
AT commands[edit | edit source]
The device is controlled using AT commands via /dev/ttymxc0 port
Serial port access example using AT commands:
root@test-noserialnumber:~# stty -F /dev/ttymxc0 115200 crtscts root@test-noserialnumber:~# microcom -s 115200 /dev/ttymxc0 +STARTUP AT OK AT OK ATZ OK ATO01 OK
GPIOs[edit | edit source]
Two GPIOs control its main functionalities via sysfs entries mapped on leds interface:
- device reset
/sys/class/leds/bt_reset/brightness
Here below a script example for resetting the BT device:
root@sdv03-lite:~# cat bt.sh echo Reset BT echo 1 > /sys/class/leds/bt_reset/brightness sleep 1 echo 0 > /sys/class/leds/bt_reset/brightness root@sdv03-lite:~#
- command mode
/sys/class/leds/bt_command_mode/brightness
Here below a script example for switch the BT device back to AT command mode (from data mode):
root@sdv03-lite:~# cat bt-command.sh echo BT set command mode echo 0 > /sys/class/leds/bt_command_mode/brightness sleep 0.5 echo 1 > /sys/class/leds/bt_command_mode/brightness root@sdv03-lite:~#
Wifi[edit | edit source]
An wifi network can be accessed using an USB wireless adapter device like the LM006.
firmware[edit | edit source]
Tipically, the wifi adapter requires a firmware file stored into the /lib/firmware directory, for example, inserting the LM006 without the firmware file, the kernel messages:
[ 39.849654] rtlwifi: Loading alternative firmware rtlwifi/rtl8192cufw.bin [ 39.856719] rtlwifi: Firmware rtlwifi/rtl8192cufw_TMSC.bin not available
while, once the correct firmware is present:
root@sdv03-lite:~# ls -la /lib/firmware/rtlwifi/ total 24 drwxr-xr-x 2 root root 4096 Dec 5 2018 . drwxr-xr-x 5 root root 4096 Dec 5 2018 .. -rw-r--r-- 1 root root 16116 Dec 5 2018 rtl8192cufw_TMSC.bin root@sdv03-lite:~#
the device is correctly initialized
root@sdv03-lite:~# [ 97.170926] usb 2-1: USB disconnect, device number 2
[ 99.273660] usb 2-1: new high-speed USB device number 3 using ci_hdrc
[ 99.425910] usb 2-1: New USB device found, idVendor=0bda, idProduct=8176
[ 99.432668] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 99.440840] usb 2-1: Product: 802.11n WLAN Adapter
[ 99.445740] usb 2-1: Manufacturer: Realtek
[ 99.449962] usb 2-1: SerialNumber: 00e04c000001
[ 99.460018] rtl8192cu: Chip version 0x10
[ 99.556498] rtl8192cu: MAC address: 5c:f3:70:1a:8a:43
[ 99.561587] rtl8192cu: Board Type 0
[ 99.565608] rtl_usb: rx_max_size 15360, rx_urb_num 8, in_ep 1
[ 99.571697] rtl8192cu: Loading firmware rtlwifi/rtl8192cufw_TMSC.bin
[ 99.581909] ieee80211 phy1: Selected rate control algorithm 'rtl_rc'
root@sdv03-lite:~# ifconfig wlan0
wlan0 Link encap:Ethernet HWaddr 5c:f3:70:1a:8a:43
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
root@sdv03-lite:~#
network scan[edit | edit source]
- the
rfkill unblockshould be issued before scanning the wireless network
root@sdv03-lite:~# rfkill unblock 0
- then using
iwcommand, the list of network will appear
root@sdv03-lite:~# iw wlan0 scan
BSS 20:aa:4b:22:55:5e(on wlan0)
TSF: 31687164214 usec (0d, 08:48:07)
freq: 2437
beacon interval: 100 TUs
capability: ESS Privacy ShortPreamble ShortSlotTime (0x0431)
signal: -44.00 dBm
last seen: 230 ms ago
Information elements from Probe Response frame:
SSID: davesrl
Supported rates: 1.0* 2.0* 5.5* 11.0* 18.0 24.0* 36.0 54.0
DS Parameter set: channel 6
ERP: <no flags>
ERP D4.0: <no flags>
Extended supported rates: 6.0* 9.0 12.0* 48.0
WPA: * Version: 1
* Group cipher: TKIP
* Pairwise ciphers: TKIP
* Authentication suites: PSK
* Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x000c)
WMM: * Parameter version 1
* u-APSD
* BE: CW 15-1023, AIFSN 3
* BK: CW 15-1023, AIFSN 7
* VI: CW 7-15, AIFSN 2, TXOP 3008 usec
* VO: CW 3-7, AIFSN 2, TXOP 1504 usec
BSS 22:aa:4b:22:55:5f(on wlan0)
TSF: 31687167783 usec (0d, 08:48:07)
freq: 2437
beacon interval: 100 TUs
capability: ESS Privacy ShortPreamble ShortSlotTime (0x0431)
signal: -48.00 dBm
last seen: 230 ms ago
Information elements from Probe Response frame:
SSID: daveguest
Supported rates: 1.0* 2.0* 5.5* 11.0* 18.0 24.0* 36.0 54.0
DS Parameter set: channel 6
ERP: <no flags>
ERP D4.0: <no flags>
Extended supported rates: 6.0* 9.0 12.0* 48.0
WPA: * Version: 1
* Group cipher: TKIP
* Pairwise ciphers: TKIP
* Authentication suites: PSK
* Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x000c)
WMM: * Parameter version 1
* u-APSD
* BE: CW 15-1023, AIFSN 3
* BK: CW 15-1023, AIFSN 7
* VI: CW 7-15, AIFSN 2, TXOP 3008 usec
* VO: CW 3-7, AIFSN 2, TXOP 1504 usec
BSS fe:3f:db:b9:b9:c9(on wlan0)
TSF: 31696360436 usec (0d, 08:48:16)
freq: 2437
beacon interval: 100 TUs
capability: ESS Privacy SpectrumMgmt ShortSlotTime (0x0511)
signal: -88.00 dBm
last seen: 240 ms ago
SSID: DIRECT-C9-HP PageWide Pro 477dw
Supported rates: 6.0* 9.0 12.0* 18.0 24.0* 36.0 48.0 54.0
DS Parameter set: channel 6
Power constraint: 0 dB
TPC report: TX power: 17 dBm
ERP: <no flags>
ERP D4.0: <no flags>
RSN: * Version: 1
* Group cipher: CCMP
* Pairwise ciphers: CCMP
* Authentication suites: PSK
* Capabilities: 16-PTKSA-RC 1-GTKSA-RC (0x000c)
HT capabilities:
Capabilities: 0x20
HT20
Static SM Power Save
RX HT20 SGI
No RX STBC
Max AMSDU length: 3839 bytes
No DSSS/CCK HT40
Maximum RX AMPDU length 32767 bytes (exponent: 0x002)
Minimum RX AMPDU time spacing: 8 usec (0x06)
HT RX MCS rate indexes supported: 0-7
HT TX MCS rate indexes are undefined
HT operation:
* primary channel: 6
* secondary channel offset: no secondary
* STA channel width: 20 MHz
* RIFS: 1
* HT protection: nonmember
* non-GF present: 0
* OBSS non-GF present: 1
* dual beacon: 0
* dual CTS protection: 0
* STBC beacon: 0
* L-SIG TXOP Prot: 0
* PCO active: 0
* PCO phase: 0
WMM: * Parameter version 1
* u-APSD
* BE: CW 15-63, AIFSN 3
* BK: CW 15-1023, AIFSN 7
* VI: CW 7-15, AIFSN 1, TXOP 3008 usec
* VO: CW 3-7, AIFSN 1, TXOP 1504 usec
WPS: * Version: 1.0
* Wi-Fi Protected Setup State: 2 (Configured)
* Response Type: 3 (AP)
* UUID: 80257526-6702-757d-ca10-7efc225144a8
* Manufacturer: HP
* Model: HP PageWide Pro 477dw MFP
* Model Number: D3Q20B
* Serial Number: CN716FX062
* Primary Device Type: 3-0050f204-1
* Device name:
* Config methods: Display
* Unknown TLV (0x1049, 6 bytes): 00 37 2a 00 01 20
* Unknown TLV (0x1049, 23 bytes): 00 01 37 10 06 00 10 80 25 75 26 67 02 75 7d ca 10 7e fc 22 51 44 a8
root@sdv03-lite:~#
wifi host spot[edit | edit source]
It is possible to create an wifi hotspot simply configuring the hostapd daemon.
- verify against supported modes
root@sdv03-lite:~# iw list | grep "Supported interface modes" -A 8
Supported interface modes:
* IBSS
* managed
* AP
* AP/VLAN
* monitor
* P2P-client
* P2P-GO
Band 1:
root@sdv03-lite:~#
- example of configuration file /etc/hostapd.conf
interface=wlan0 ssid=sdv03-test channel=1 wpa=2 wpa_passphrase=sdv03password wpa_key_mgmt=WPA-PSK wpa_pairwise=TKIP rsn_pairwise=CCMP
- kill any wpa_supplicant daemon and unblock rfkill
root@sdv03-lite:~# killall wpa_supplicant root@sdv03-lite:~# rfkill unblock wifi
- start the hostapd
root@sdv03-lite:~# /etc/init.d/hostapd start Starting HOSTAP Daemon: Configuration file: /etc/hostapd.conf [ 823.569111] rtl8192cu: MAC auto ON okay! [ 823.606635] rtl8192cu: Tx queue select: 0x05 [ 824.472331] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready Using interface wlan0 with hwaddr 5c:f3:70:1a:8a:43 and ssid "sdv03-test" random: Only 12/20 bytes of strong random data available from /dev/random random: Not enough entropy pool available for secure operations WPA: Not enough entropy in random pool for secure ope[ 824.551065] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready rations - update keys later when the first station connects wlan0: interface state UNINITIALIZED->ENABLED wlan0: AP-ENABLED hostapd. root@sdv03-lite:~#
- show wlan0 status
root@sdv03-lite:~# iw wlan0 info
Interface wlan0
ifindex 5
wdev 0x100000001
addr 5c:f3:70:1a:8a:43
ssid sdv03-test
type AP
wiphy 1
channel 1 (2412 MHz), width: 20 MHz (no HT), center1: 2412 MHz
root@sdv03-lite:~#
- configure dhcpd server (it is possible to use, for example, busybox-udhcpd-1.24.1 as dhcpd daemon) and start it
root@sdv03-lite:~# cat /etc/udhcpd.conf start 192.168.1.10 end 192.168.1.250 interface wlan0 siaddr 192.168.1.1 option lease 864000 root@sdv03-lite:~# /etc/init.d/busybox-udhcpd start starting Busybox UDHCP Server: udhcpd... done. root@sdv03-lite:~#
